Interesting.
Please note, I'm not an attorney or expert on Java.
The complaint is quite vague overall, perhaps deliberately. It lists the various patents, says what they are, and alleges that Google infringed upon each one. It also suggests that Sun/Oracle owns heaps of Java source code which has been used by Google, thereby breaching copyright. Oh, and since I own an Android phone I too am infringing on their patents, but fortunately they lay the blame for this at Google's feet. Whew!
Nowhere in the complaint is there any explanation of what licensing obligations were applicable or which govern the distribution of Java. Nor is it clear when Oracle alleges this infringement began in relation to each patent, or why or how they consider it to be infringed upon by Android. The complaint mentions the Dalvik VM specifically.
Looking through the licensing information on the phone itself, there's a bunch of stuff from Sun under a 1993-4 license which is very short and confers the right to use, modify and distribute the software without reservation. Most of the rest is under the Apache Harmony license, and a sprinkling of others. Well, I suppose if google were deliberately infringing, they would hardly mention the fact in their licensing statements.
So where is the problem?
14. On information and belief, Google has been aware of Sun’s patent portfolio, including the patents at issue, since the middle of this decade, when Google hired certain former Sun Java engineers.
A good ZDnet article suggests the engineers in question may be 'Lars Bak, Robert Griesemer, and Frank Yellin, all former Sun employees who now work for Google on Java and Web browser technologies, and all of whom appear as inventors on one or more of the patents in question.'
http://www.zdnet.com/blog/burnette/oracle-uses-james-gosling...
Also (possibly, IMHO) http://en.wikipedia.org/wiki/Joshua_Bloch
I don't know what Oracles chances are. On the surface it looks like rather weak sauce, with some of the patents being questionable because of prior art...but like I said, that's an amateur perspective. Oracle appears to be saying the bare minimum necessary at this time. Google will likely move for a summary judgment of dismissal, denying that there is any substance to Oracle's claims, and at that point Oracle may have to make some more specific allegations.